How to Tell If Your Microwave is Vented Outside
What to know

How to Tell If Your Microwave is Vented Outside?

A microwave has multiple methods of venting off heat from inside it to keep itself from overheating. How it goes about venting itself depends on where its vents are located, if it’s using a ventilation fan (mostly OTRs and their 300-400 CFM fans), and how much space is needed around it to do venting.

How Do You Tell If Your Microwave is Vented Outside?

During the installation of your microwave into your under-cabinet, above-cabinet, or over-the-range placement, you will be informed about how you’ll go about ventilation and whether the unit supports ductless or ducted vents.

Check your cabinet above the microwave for a duct that directs exhaust outside your home if your microwave contains intake vents on the bottom of it.

The vent is sometimes connected to the back wall behind the device instead of going through the cabinet above the microwave if it’s vented to the outside of your abode.

The Vents on a Microwave
The Vents on a Microwave

What is a Self-Venting Microwave?

A microwave using an externalized venting system vents to the outside of your home using ducts. A microwave without ducts vents by itself. You can convert designated convertible microwaves to a recirculating venting system if you install the correct components to it.

Ducted ventilation ensures that your kitchen doesn’t get filled with heat or toxicity as you cook, bake, or microwave anything since all that air is vented outside through the ductwork. Other kitchens go about venting by being near an outdoor exit—just open a door to vent the heat out.

A recirculating microwave is a microwave that vents internally or back to your kitchen. In the case of a built-in microwave, it vents from within the cabinet it’s installed into.

Do OTR Microwaves Require Ventilation?

Well, yes. Ironically, the whole purpose of the OTR is to double as a hood vent with microwave features to save space on your counter and replace any existing hood vents over the stovetop you might have.

Furthermore, virtually all building codes require you to install over your kitchen stove a fully functioning ventilation system. This system typically includes a bulb that shines a light over your stovetop and a fan with a high rating for cubic feet per minute (CFM).

It’s this fan that removes smoke, steam, and heat over the air whenever you cook. When shopping for an OTR, you typically recommend getting at least one with a 300 CFM fan installed

Where are the Vents on a Microwave?

Typically, the external exhaust vent of your OTR microwave is located on top of it. It vents out to the roof. It also appears to come out of the top at the front of the device if you’re venting back into the room via the recirculating ventilation system.

The pickup is under the microwave, above the range. It typically comes with grease screens to shield against grease accumulation as you cook. Most countertop or non-installed (not built-in) microwaves are of the recirculation vent type.

Do Microwave Vents Work or Not?

A microwave that’s externally vented while mounted over a cooktop (OTR) typically uses the aforementioned high-CFM fan to draw air through its vents and into an exhaust duct leading to the home or building’s exterior.

When it’s installed, it practically requires this, because it’s designed to replace the range hood that should also be externally vented. Through this, all the particulate matter, heat, moisture, and odor generated when you cook goes directly outdoors.

How Do You Know a Range Hood is Vented?

The range hood could be vented straight through a wall, leading to exhaust ports to the outside. You can tell if it’s the case by going outside and looking at the wall to see if there’s a wall cap. This allows the escape or exit of vented air from the kitchen.

Naturally, the range hood probably won’t be vented outdoors if it isn’t mounted on an outside wall. This might instead mean you have indoor ventilation requiring opening doors and windows instead of ductwork handling ventilation for you.

Can You Put a Microwave Inside a Cabinet? 

Yes, you can. They’re called built-in microwaves and they typically lack an outer shell because that part is covered by the deep cabinet cavity itself. Its face then becomes the cabinet door and you can access it like a cabinet you can cook things in.

It helps save you kitchen space and countertop real estate for all your meal prep needs. The more space you have to gather your ingredients, knead your dough, chop those vegetables, mince those meats, and prepare your special flavorful sauces, the better.

Also, did you know that certain freestanding microwaves can be converted into built-in microwaves you can place inside your cabinet?

Can You Install a Countertop Microwave Inside a Cabinet?

It’s not only built-ins specifically designed for cabinet placement that could be put inside your cabinet. Certain manufacturers have trim kits available to convert any countertop microwave in their brand line into a built-in.

To go back to the original topic, ventilation of natural built-ins and repurposed built-ins from countertop microwaves require that your cabinet has ample space to allow it to vent out heat and odors away.

Clearance Requirements for Ventilation

Your cabinet should have a minimum of three inches of space on nearly all sides of your microwave except its bottom and its back (which only require an inch or more of space). The cabinet should also typically be 15 inches deep.

Certain experts, however, recommend against installing a countertop into a cabinet. They recommend using built-ins designed to be built into cabinets without an outer shell for most of its exposed circuitry.

Issues to Keep in Mind

A microwave is self-venting if it doesn’t use or need ductwork to vent, instead of using a recirculating venting system to vent out the heat and smells back to the kitchen. From there, if you have a kitchen with an outdoor exit, you can open the door to let all the bad air out.

Otherwise, the vents of your kitchen can handle removing all that heat and smells, evacuating them outdoors. Long story short, the difference between a ductless and ducted microwave root from whether or not you need to hook up a ventilation system for the device.


  1. How do you tell if your microwave is vented outside?“,, Retrieved August 18, 2021
  2. Can You Put a Microwave in a Cabinet?“,, Retrieved August 18, 2021
  3. What is a self venting microwave?“,, Retrieved August 18, 2021

Through the years, the microwave oven has become a standard appliance for all homes. It is safe to say that there is no home without a microwave oven. If you are looking for a microwave oven that best fits your needs, You find the right website.

Leave a Reply

Your email address will not be published. Required fields are marked *